Devices, systems and methods for treating tissue regions of the body

ABSTRACT

Improved devices, systems and methods for treating a tissue region provide straightforward, yet reliable ways for installing diverse functional components within the confined space of a catheter-based instrument.

FIELD OF THE INVENTION

The invention is directed to devices, systems and methods for treatingtissue regions of the body.

BACKGROUND OF THE INVENTION

Catheter based instruments are widely used to gain access to interiorbody regions for diagnostic or therapeutic purposes. The size of suchinstruments are constrained by the need to permit deployment and usewithin relatively small, confined areas of the body. Still, there is theneed for such instruments to carry one or more functional components,e.g., to ablate body tissue and/or to convey fluid into contact withtissue in the targeted tissue region and/or to sense local tissueconditions, etc.

The challenge persists in accommodating the need for small, easilydeployed catheter-based instruments with the demand for reliable androbust functionality.

SUMMARY OF THE INVENTION

The invention provides improved devices, systems and methods fortreating a tissue region that provide straightforward, yet reliable waysfor installing diverse functional components within the confined spaceof a catheter-based instrument.

One aspect of the invention provides a support assembly for an elongatedelectrode element. The support assembly comprises at least one spine forholding the elongated electrode element for use. The spine peripherallydefines at least one spine lumen. The support assembly also includes aninsert carried by the spine. The insert peripherally defines an insertlumen sized to accommodate forward and rearward sliding movement of theelongated electrode element within the spine. The insert includes adistal extension having an outer dimension sized for insertion into thespine lumen. The insert also includes a proximal region having an outerdimension sized to resist insertion into the spine lumen, to therebydefine a maximum insertion length for the distal extension into thespine lumen.

In one embodiment, the spine includes a side opening, and the distalextension of the insert includes an open distal end. In thisarrangement, the maximum insertion length places the open distal end indesired alignment with the side opening for guiding sliding movement ofa distal portion of the elongated electrode element toward the sideopening.

In one embodiment, the spine includes an interior ramp that depends fromthe side opening. In this arrangement, the maximum insertion lengthlocates the open distal end of the insert on the interior ramp forguiding sliding movement of a distal portion of the elongated electrodeelement toward the side opening.

In one embodiment, the maximum insertion length keeps the distal end ofthe insert from projecting through the side opening.

Another aspect of the invention provides an electrode assembly. Theassembly comprises an elongated electrode element having a distaloperative portion. A connector to couple the elongated electrode elementto a source of radio frequency energy. The assembly also mounts theelongated electrode element for sliding movement within an insert in aspine, as previously described.

Another aspect of the invention provides a method for making a supportassembly for an elongated electrode element. The method provides atleast one spine with a lumen for holding the elongated electrode elementfor use. The method forms a side opening in the spine in communicationwith the spine lumen. The method also provides an insert for the spinelumen. The insert peripherally defines an insert lumen sized toaccommodate forward and rearward sliding movement of the elongatedelectrode element within the spine. The insert includes a distalextension having an outer dimension sized for insertion into the spinelumen. The insert also includes a proximal region having an outerdimension sized to resist insertion into the spine lumen.

The method inserts the distal extension through the spine lumen andoutward beyond the side opening until the proximal region resistsfurther insertion. The method cuts the distal extension flush with theside opening to form an open distal end. The cutting also defines amaximum insertion length for the distal extension.

In one embodiment, the method secures the proximal region of the insertto the spine.

In one embodiment, after performing the cutting step, the method movesthe proximal region of the insert a short distance from the spine towithdraw the open distal end into the spine lumen. Afterwards, themethod can secure the proximal region of the insert to the spine.

In one embodiment, the method forms an interior ramp that depends fromthe side opening. In this arrangement, the distal extension is insertedthrough the spine lumen and outward beyond the side opening along theinterior ramp.

In one arrangement, after performing the cutting step, the method movesthe proximal region a short distance from the spine to withdraw the opendistal end into the spine lumen to rest on the interior ramp. Afterward,the method can secure the proximal region of the insert to the spine.

Another aspect of the invention provides systems and methods forhandling fluid to or from an operative element carried by a cathetertube. The systems and methods provide a manifold body sized to fitwithin the catheter tube. The manifold body includes a single main fluidjunction, multiple branch fluid junctions, and a fluid circuit formedwithin the manifold body to channel fluid flow between the single mainfluid junction and the multiple branch fluid junctions. The systems andmethods couple the single main fluid junction to a fluid source or afluid destination external to the catheter tube. The systems and methodscouple each of the multiple branch fluid junctions individually to afluid-conveying port on the operative element. The systems and methodsmount the manifold within the catheter tube.

Features and advantages of the inventions are set forth in the followingDescription and Drawings, as well as in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a system for treating tissue that includesa treatment device that embodies features of the invention;

FIG. 2 is a perspective view, with portions broken away and in section,of the treatment device shown in FIG. 1, with the basket element carriedby the device shown in a collapsed condition for deployment to atargeted tissue region;

FIG. 3 is a perspective view, with portions broken away, of thetreatment device shown in FIG. 1, with the basket element carried by thedevice shown in an expanded condition, as it would be when ready for usein a targeted tissue region;

FIG. 4 is a perspective view, with portions broken away, of thetreatment device shown in FIG. 1, with the basket element carried by thedevice shown in an expanded condition, and with electrodes carried bythe basket element extended for use in a targeted tissue region;

FIG. 5 is an enlarged end view of one of the multiple lumen spines thatform the basket element shown in FIGS. 2 to 4, showing the multipleinterior lumens that the spine possesses;

FIG. 6 is a top view of the multiple lumen spine shown in FIG. 5,showing the different functional elements that the interior lumens ofthe spine carry;

FIG. 7 is a schematic view of the interior of the catheter tube andhandle of the treatment device shown in FIGS. 2 to 4, showing therouting of different functional elements within the confined space ofthe catheter tube;

FIG. 8 is an enlarged view of a portion of one of the multiple lumenspines that form the basket element shown in FIGS. 2 to 4, showing anelectrode deployed through an opening in one of the spines;

FIG. 9 is a side view of the electrode shown in FIG. 8, out ofassociation with the spine;

FIG. 10 is a side section view of the lumen of the spine shown in FIG.5, in which the electrode shown in FIG. 9 is carried, showing an insertthat guides passage of the electrode within the spine, and showing theelectrode in an extended position for use;

FIGS. 11 to 15 are side sectional views showing the assembly of theinsert shown in FIG. 10 into the spine;

FIG. 16 is a side section view of the lumen of the spine shown in FIG.10, showing the electrode in a retracted position within the insert;

FIG. 17 is a perspective view of an irrigation manifold that thetreatment device shown in FIG. 1 possesses, to route fluid within thecatheter tube from a single source to several basket spines;

FIG. 18 is a distal end view of the irrigation manifold shown in FIG.17;

FIG. 19 is a proximal end view of the irrigation manifold shown in FIG.17;

FIG. 20 is a side section view of the irrigation manifold shown in FIG.17 taken generally along line 20—20 in FIG. 19; and

FIG. 21 is a schematic view of the irrigation manifold shown in FIG. 17positioned within the catheter tube of the treatment device shown onFIG. 1, and serving to channel fluid from a source simultaneously toseveral basket spines.

The invention may be embodied in several forms without departing fromits spirit or essential characteristics. The scope of the invention isdefined in the appended claims, rather than in the specific descriptionpreceding them. All embodiments that fall within the meaning and rangeof equivalency of the claims are therefore intended to be embraced bythe claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

This Specification discloses various catheter-based systems and methodsfor treating dysfunction in various locations in an animal body. Forexample, the various aspects of the invention have application inprocedures requiring treatment of sphincters and adjoining tissueregions in the body, or hemorrhoids, or incontinence, or restoringcompliance to or otherwise tightening interior tissue or muscle regions.The systems and methods that embody features of the invention are alsoadaptable for use with systems and surgical techniques that are notnecessarily catheter-based.

The systems and methods are particularly well suited for treatingdysfunctions in the upper gastrointestinal tract, e.g., in the loweresophageal sphincter and adjacent cardia of the stomach. For thisreason, the systems and methods will be described in this context.Still, it should be appreciated that the disclosed systems and methodsare applicable for use in treating other dysfunctions elsewhere in thebody, which are not necessarily sphincter-related.

I. Overview

A tissue treatment device 26 is shown in FIG. 1. The device 26 includesa handle 28 made, e.g., from molded plastic. The handle 28 carries aflexible catheter tube 30. The catheter tube 30 can be constructed, forexample, using standard flexible, medical grade plastic materials, likevinyl, nylon, poly(ethylene), ionomer, poly(urethane), poly(amide), andpoly(ethylene terephthalate). The handle 28 is sized to be convenientlyheld by a physician, to introduce the catheter tube 30 into the tissueregion targeted for treatment. The catheter tube 30 may be deployed withor without the use of a guide wire (not shown).

The catheter tube 30 carries on its distal end an operative element 36.The operative element 36 can take different forms and can be used foreither therapeutic purposes, or diagnostic purposes, or both. Theoperative element 36 can support, for example, a device for imaging bodytissue, such as an endoscope, or an ultrasound transducer. The operativeelement 36 can also support a device to deliver a drug or therapeuticmaterial to body tissue. The operative element 36 can also support adevice for sensing a physiological characteristic in tissue, such aselectrical activity, or for transmitting energy to stimulate tissue orto form lesions in tissue.

In the illustrated embodiment (shown in greater detail in FIGS. 2, 3,and 4), one function that the operative element 36 performs is to applyenergy in a selective fashion to a targeted tissue region. For thepurpose of illustration, the targeted tissue region can comprise, forexample, the lower esophageal sphincter, or cardia of the stomach, orboth. The applied energy creates one or more lesions, or a prescribedpattern of lesions, below the mucosal surface of the esophagus orcardia. The subsurface lesions are formed in a manner that preserves andprotects the mucosal surface against thermal damage. The natural healingof the subsurface lesions leads to a physical tightening of thesphincter and/or adjoining cardia. The subsurface lesions can alsoresult in the interruption of aberrant electrical pathways that maycause spontaneous sphincter relaxation. In any event, the treatment canrestore normal closure function to the sphincter.

In this arrangement (as FIG. 1 shows), the treatment device 26 canoperate as part of a system 24. The system 24 includes a generator 38 tosupply the treatment energy to the operative element 36.

A cable 40 is coupled to the handle 28. The cable 40 is electricallycoupled to the operative element 36 by wires that extend through thecatheter tube 30. The cable 40 is also electrically coupled to thegenerator 38, to convey the generated energy to the operative element36.

In the illustrated embodiment, the generator 38 supplies radio frequencyenergy, e.g., having a frequency in the range of about 400 kHz to about10 mHz. Of course, other forms of energy can be applied, e.g., coherentor incoherent light; heated or cooled fluid; resistive heating;microwave; ultrasound; a tissue ablation fluid; or cryogenic fluid.

The system 24 can also include certain auxiliary processing equipment.In the illustrated embodiment, the processing equipment comprises anexternal fluid delivery or irrigation apparatus 44. A luer fitting 48 onthe handle 28 couples to tubing 34 to connect the treatment device 26 tothe fluid delivery apparatus 44, to convey processing fluid fordischarge by or near the operative element 36.

The system 24 also desirably includes a controller 52. The controller 52is linked to the generator 38 and the fluid delivery apparatus 44. Thecontroller 52, which preferably includes an onboard central processingunit, governs the power levels, cycles, and duration that the radiofrequency energy is distributed to the operative element 36, to achieveand maintain power levels appropriate to achieve the desired treatmentobjectives. In tandem, the controller 52 also desirably governs thedelivery of processing fluid.

The controller 52 desirably includes an input/output (I/O) device 54.The I/O device 54 allows the physician to input control and processingvariables, to enable the controller to generate appropriate commandsignals.

II. The Operative Element

In the embodiment shown in FIGS. 2 to 4, the operative element 36comprises a three-dimensional basket 56. The basket 56 includes one ormore spines 58, and typically includes from four to eight spines 58,which are assembled together by a distal hub 60 and a proximal base 62.In FIGS. 2 to 4, four spines 58 are shown, which are equallycircumferentially spaced apart.

Each spine 58 preferably comprises a flexible body made, e.g. frommolded plastic, stainless steel, or nickel titanium alloy. Candidateplastic materials for the spine 58 include PEEK, Ultem, polyimide,Pebax, Hytrel polyester, PET, and polyurethane.

The cross sectional shape of the spine body 58 can vary, possessing,e.g., a circular, elliptical, square, or rectilinear shape. In theillustrated embodiment, the spine bodies 58 each possess a rectilinearshape to resist twisting.

In the illustrated embodiment (see FIG. 5), each spine body 58 definestwo or more interior lumens or passages. As FIG. 5 shows, in theillustrated embodiment, three lumens or passages, designated L1, L2, andL3, are present. For each spine 58, each passage L1, L2, and L3 isdedicated to accommodate a different functional element.

In the illustrated embodiment (see FIGS. 6 and 7), a first or centerpassage L1 carries a movable, elongated electrode element 66. A secondpassage L2 along one side the first passage L1 carries a temperaturesensing element 80. A third passage L3 along the opposite side of firstpassage L1 is coupled to tubing 82 that carries processing fluid fromthe fluid delivery device 44.

A. The Electrodes

Each electrode 66 is carried within the first passage L1 for slidingmovement. Each electrode 66 slides from a retracted position, withdrawnin the spine 58 (as shown in FIG. 3), and an extended position,extending outward from the spine 58 through an opening 84 in the spine58 (as shown in FIGS. 4 and 8).

As FIG. 7 best shows, a push-pull lever 68 on the handle 28 (as FIGS. 2to 4 also show) is coupled by a stylet 86 to a carrier 88 located withinthe catheter tube 30. The electrodes 66 are secured to the carrier 88,extending from the carrier 88 into the lumens L1 of the respective spine58. The lever 68 controls the sliding movement of the electrodes withthe spines 58 between the retracted position (by pulling rearward on thelever 68, arrow 90 in FIG. 7) and the extended position (by pushingforward on the lever 68, arrow 92 in FIG. 7).

As FIGS. 2 to 4 show, the lever 68 is exposed on the handle 28 formanipulation by the thumb of an operator. A suitable rachet assembly 118(see FIG. 2) may be provided to advance the sliding movement of thelever 68 in a controlled, stepwise fashion. A slot 119 on the handle 28stops advancement of the lever 68 beyond a predetermined distance.

In the illustrated arrangement, the electrodes 66 are intended formonopolar operation. Each electrode 66 serves as a transmitter ofenergy, and an indifferent patch electrode on the patient's skin (notshown) serves as a common return for all electrodes 66. It should beappreciated, however, the operative element 36 could include bipolarpairs of electrodes 66, if desired.

In the embodiment shown in FIGS. 2 to 4, an expandable structure 72comprising, e.g., a balloon, is located within the basket 56. Theballoon structure 72 can be made, e.g., from a PolyethyleneTerephthalate (PET) material, or a polyamide (non-compliant) material,or a radiation cross-linked polyethylene (semi-compliant) material, or alatex material, or a silicone material, or a C-Flex (highly compliant)material. Non-compliant materials offer the advantages of a predictablesize and pressure feedback when inflated in contact with tissue.Compliant materials offer the advantages of variable sizes and shapeconformance to adjacent tissue geometries.

The balloon structure 72 presents a normally, generally collapsedcondition, as FIG. 2 shows. In this condition, the basket 56 is alsonormally collapsed about the balloon structure 72, presenting a lowprofile for deployment into the targeted tissue region.

The catheter tube 30 includes an interior lumen 94 (see FIG. 3), whichcommunicates with the interior of the balloon structure 72. A fitting 76(e.g., a syringe-activated check valve) is carried by the handle 28. Thefitting 76 communicates with the lumen. The fitting 76 couples the lumen94 to a syringe 78 (see FIG. 3), which injects fluid under pressurethrough the lumen 94 into the balloon structure 72, causing itsexpansion, as FIG. 3 shows.

Expansion of the balloon structure 72 urges the spines 58 of the basket56 to open and expand (as FIG. 3 shows). The force exerted by theballoon structure 72 upon the spines 58, when expanded, is sufficient toexert an opening force upon the tissue surrounding the basket 56. Whenmoved to their extended positions, the electrode 66 penetrate tissuecontacted by the spines 58.

The electrodes 66 can be formed from various energy transmittingmaterials. For deployment in the esophagus or cardia of the stomach, theelectrodes 66 are formed, e.g., from nickel titanium. The electrodes 66can also be formed from stainless steel, e.g., 304 stainless steel, or,as will be described later, a combination of nickel titanium andstainless steel. The electrodes 66 have sufficient distal sharpness andstrength to penetrate a desired depth into the smooth muscle of theesophageal or cardia wall. The desired depth can range from about 4 mmto about 5 mm.

To further facilitate penetration and anchoring in the targeted tissueregion, each electrode 66 is preferably biased with a bend (as FIGS. 4and 8 show) Movement of the electrode 66 into the spine 58 overcomes thebias and straightens the electrode 66 for passage through the lumen L1.

In the illustrated embodiment (see FIGS. 4 and 8), each electrode 66 isnormally biased with an antegrade bend (i.e., bending toward theproximal base 62 of the basket 56). Alternatively, each electrode 66 canbe normally biased toward an opposite retrograde bend (i.e., bendingtoward the distal hub 60 of the basket 58).

An electrical insulating material 70 (see FIG. 9) is desirably coatedabout the distal end of each electrode 66, a distance below the distaltip. For deployment in the esophagus or cardia, the length of theinsulating material 70 ranges from about 80 to about 120 mm. Theinsulating material can comprise, e.g., a Polyethylene Terephthalate(PET) material, or a polyimide or polyamide material. For deployment inthe esophagus or cardia, each electrode 66 preferably presents anexposed, non-insulated conductive length of about 8 mm. When the distalend of the electrode 66 that penetrates the targeted tissue regiontransmits radio frequency energy, the material 70 insulates the surfaceof the tissue region from direct exposure to the radio frequency energy.

Desirably (see FIG. 10), the electrode 66 slides within an insert 96positioned within the first passage L1. The insert 96 guides theelectrode 66 to the electrode opening 84 and protects the spine 58 frominadvertent puncture or “poke-through” by the electrode 66.

The insert 96 is preferably made of a relatively hard (i.e., highdurometer) and tough plastic material, e.g., PEEK plastic. This plasticmaterial has a durometer in excess of 75 Shore D. The hardness provideslubricity for easy electrode movement within the insert 96, and thetoughness makes the insert 96 resistant to puncture by the electrode 66.The insert material desirably is also adhesively bondable, which PEEKplastic is. Desirably, the insert is also reformable with heat, whichPEEK plastic is, so that its outer diameter can be readily altered indesired ways during manufacture, as will be described in greater detailbelow.

Other candidate materials for the insert 96 include Ultem, polyimide,Pebax, Hytrel polyester, PET, and polyurethane.

A main advantage of the insert 96 is absolute guidance of the electrode66 through the spine opening 84. The flexibility to provide an insert 96of a different material and possessing different mechanical propertiesthan a spine 58 is another advantage. The insert 96 can also have adifferent wall thickness than the spine body 58, so that the dimensionsof each of these components can be made appropriate to the function theyperform.

As FIG. 10 shows, the insert 96 includes a first body portion 98 and asecond body portion 100. The first body portion 96 has an outsidediameter smaller than the inner diameter of the passage L1, toaccommodate insertion of the first body portion 98 into the passage L1.The second body portion 100 has an outside diameter that is larger thanthe inner diameter of the passage L1, to prevent its insertion into thepassage. The transition between the first and second body portions 98and 100 forms a notch 102 that abuts against the proximal end 116 of thespine 58. This abutment forms a mechanical stop, to prevent movement ofthe first body portion 98 within the passage L1 beyond a prescribeddistance.

In this arrangement (see FIG. 9), the electrode 66 may comprise a hybridof materials comprising stainless steel for the proximal portion 104 andnickel titanium alloy for the distal portion 106. The nickel titaniumalloy performs best in the curved distal portion 106 of the electrode66, due to its super-elastic properties. The use of stainless steel inthe proximal portion 104 can reduce cost, by minimizing the amount ofnickel titanium alloy required.

The different materials may be joined, e.g., by crimping, swaging,soldering, welding, or adhesive bonding, which provide electricalcontinuity between or among the various materials.

The distal portion 106 of the electrode 66 possesses an outside diameterless than the inner diameter of the insert 96. This allows the distalportion 106 of the electrode 66 to freely slide within the insert 96.The proximal portion 104 of the electrode has an outside diameter thatis larger than the inner diameter of the insert 96. The transitionbetween the distal and proximal portions 106 and 104 of the electrode 66forms a notch 108 that abuts against the notch 102 formed at thetransition between the first and second body portions 98 and 100 of theinsert 96.

In assembly (see FIG. 11), the electrode opening 84 is formed in thespine 58 by a heat gun 112 or the like in the desired located on theexterior of the passage L1. As FIG. 12 shows, a segment 110 of the spinewall is displaced into the passage L1 as the opening 84 is created. Thiswall segment 110 is deflected into the passage L1, to form an interiorramp appended to the opening 84.

As FIG. 13 shows, the first body portion 98 of the insert 96 is insertedthrough the proximal end 116 of the spine 58 into the passage L1. Thefirst body portion 98 is advanced through the formed opening 84 to thefullest extent permitted, i.e., until the notch 102 between the firstand second body portions 98 and 100 abuts against the proximal end 116of the spine 58.

As FIG. 14 shows, the first body portion 98 that projects from theopening 84 is cut to form a terminus 112 that is flush with the opening84. The insert 96 is then pulled back a small distance (see FIG. 15), sothat the terminus 112 rests within the passage L1 against the ramp wallsegment 110, a small distance below the plane of the opening 84.Adhesive 114 is applied in the space between the notch 102 and theproximal end 116 of the spine 58, to thereby secure the insert 96 to thebody of the spine 58. As FIG. 16 shows, the distal portion 106 of theelectrode 66 freely slides through the insert 96 in response tooperation of the push-pull lever 68 previously described. The insertterminus 112 faces toward the opening 84, and serves to reliably guidethe distal portion 106 of the electrode 66 toward and away from theopening 84. The eventual abutment between the lever 68 and the slot 119on the handle 28 (see FIG. 2) will mechanically stop further passage ofthe distal portion 106 of the electrode 66 through the opening 84. Thedepth of electrode penetration into tissue is thus mechanicallycontrolled, to prevent puncture through the targeted tissue region.

Should the adhesive 114 fail, the eventual abutment of the notch 102(between the first and second body portions 98 and 100 of the insert 96)against the proximal end 116 of the spine 58 will mechanically limit theextent to which the insert terminus 112 can advance through the opening84. The mechanically limited displacement of the insert terminus 112through the opening 84 serves to prevent exposure of the cut insertterminus 112 beyond the plane of the electrode opening and into contactwith tissue.

The electrodes 66 can be formed in various sizes and shapes. Theelectrodes 66 can possess a circular cross sectional shape. However, theelectrodes 66 preferably possess a cross section that provides increasedresistance to twisting or bending as the electrodes penetrate tissue.For example, the electrodes 66 can possess a rectangular cross section.Alternatively, the electrodes 66 can possess an elliptical crosssection. Other cross sections, e.g., conical or pyramidal, can also beused to resist twisting.

The surface of the electrode 66 can, e.g., be smooth, or textured, orconcave, or convex. The preceding description describes electrodes 66bent in either an antegrade or retrograde direction over an arc ofninety degrees or less. The bend provides a secure anchorage in tissue.Retraction of the electrodes 66 into the insert overcomes the bias andstraightens the electrode 66 when not in use.

B. Surface Cooling

In the illustrated embodiment (see FIG. 6), the fluid delivery apparatus44 conveys processing fluid through the third passage L3 in the spine 58for discharge at the treatment site. The processing fluid F cancomprise, e.g., saline or sterile water, to cool surface tissue whileenergy is being applied by the electrode 66 to ohmically heat muscle ortissue beneath the surface, to thereby protect the surface tissue fromthermal damage.

The third passage L3 conveys liquid from the irrigation apparatusthrough an opening 120 formed in the spine 58. The irrigation opening120 in each spine 58 is generally aligned with the needle opening 84 inthe spine 58, so that ablation and cooling occur in the same generaltissue region.

In the illustrated embodiment (see FIG. 7), the individual lengths oftubing 82 that convey irrigation fluid to each passage L3 of the spines58 are coupled to an irrigation manifold 122 within the catheter tube30. The irrigation manifold 122 is, in turn, coupled by a single tube124 to the luer fitting 48 on the handle 28, previously described (seeFIG. 1). The irrigation manifold 122 simplifies connection of themultiple tubing 82 to the single tube 124 within the confined space ofthe catheter tube 30 (as FIG. 21 shows), as well as efficiently routescooling fluid to the appropriate openings 120.

The irrigation manifold 122 can be constructed in various ways, e.g.,from molded or machined plastic such as polycarbonate or Ultem. In theillustrated embodiment (see FIGS. 17 to 20), the manifold 122 is formedfrom plastic to form a compact body 134 sized to fit within the cathetertube. The manifold body including a single main fluid junction or inletport 130, multiple branch fluid junctions or apertures 128, and a fluidcircuit 126 formed within the manifold body 134 to channel fluid flowbetween the single main fluid junction 130 and the multiple branch fluidjunctions 128. The single tube 124 is secured to the main fluid junction130(see FIG. 21), e.g., by an adhesive bond. The multiple branch fluidjunctions or apertures 128, which are sized and arranged side-by-side toreceive individual ends of the tubings 82 (see FIG. 21), e.g., byadhesive bonds. The apertures 128 desirably include internal tubingstops to facilitate accurate adhesive bonding. The manifold 122 is alsodesirably made from a clear or transparent plastic, to furtherfacilitate the process of adhesive bonding the tubings 82 within theapertures 128. The tubings 82 extend from the manifold 122 and arerouted to the designated passages L3 in the spines 58. The cavity 126distributes irrigation fluid conveyed through the single tube 124 to theindividual tubings 82 serving the spines 58.

In a representative embodiment, the manifold body 134 can measure about0.74 inch in overall maximum length (from apertures 128 to the end ofthe inlet port 130) and about 0.274 inch in maximum width.

It should be appreciated that the manifold 122 can serve to handle fluidflow either to (i.e, fluid irrigation) or from (i.e., fluid aspiration)an operative element carried by a catheter tube. The manifold body forcarrying out either function is sized to fit within the catheter tube.The manifold body is machined or molded as a single unit to including asingle main fluid junction (inlet 130), multiple branch fluid junctions(apertures 128), and a fluid circuit (circuit 126) to channel fluid flowbetween the single main fluid junction and the multiple branch fluidjunctions. The single main fluid junction can be coupled either to afluid source or a fluid destination external to the catheter tube.Likewise, each of the multiple branch fluid junctions can beindividually coupled to a fluid-conveying port on the operative element.

C Temperature Sensing

In the illustrated embodiment (see FIGS. 6 and 7), the second passage L2in each spine 58 carries a temperature sensing element 80. In theillustrated embodiment, the temperature sensing element 80 comprises athermocouple assembly. The temperature sensor is exposed through anopening 140 in the spine body 38. The temperature sensor rests againstsurface tissue when the basket structure is deployed for use. Desirably(as FIG. 6 shows), the temperature sensor opening 140 is generallyaligned with the electrode and cooling fluid openings 84 and 120, sothat ablation, temperature sensing, and cooling occur generally in thesame localized tissue region.

As FIG. 7 shows, the individual thermocouple wires 80 extend from therespective passages L2. The thermocouple wires 80 are desirably wound toform a composite thermocouple cable 142. The thermocouple cable 142extends through the catheter tube 30 into the handle 28. Thethermocouple cable 142 is electrically coupled (via the cable 40) totemperature sensing and processing elements of the controller 52.

The I/O device 54 of the controller 52 receives real time processingfeedback information from the temperature sensors 80, for processing bythe controller 52, e.g., to govern the application of energy and thedelivery of processing fluid. The I/O device 54 can also include agraphical user interface (GUI), to graphically present processinginformation to the physician for viewing or analysis.

Various features of the invention are set forth in the following claims.

We claim:
 1. A support assembly for an elongated electrode elementcomprising at least one spine for holding the elongated electrodeelement for use, the spine peripherally defining at least one spinelumen, and an insert carried by the spine and peripherally defining aninsert lumen sized to accommodate forward and rearward sliding movementof the elongated electrode element within the spine, the insertincluding a distal extension having a first outer dimension sized forinsertion into the spine lumen, the insert also including a proximalregion having a second outer dimension greater than the first outerdimension and sized to resist insertion into the spine lumen to therebydefine a maximum insertion length for the distal extension.
 2. Anassembly according to claim 1 wherein the spine includes a side opening,wherein the distal extension of the insert includes an open distal end,and wherein the maximum insertion length places the open distal end indesired alignment with the side opening for guiding sliding movement ofa distal portion of the elongated electrode element toward the sideopening.
 3. An assembly according to claim 1 wherein the spine includesa side opening and an interior ramp depending from the side opening,wherein the distal extension of the insert includes an open distal end,and wherein the maximum insertion length locates the open distal end onthe interior ramp for guiding sliding movement of a distal portion ofthe elongated electrode element toward the side opening.
 4. An assemblyaccording to claim 1 wherein the spine includes a side opening, whereinthe distal extension of the insert includes a distal end, and whereinthe maximum insertion length keeps the distal end from projectingthrough the side opening.
 5. An assembly according to claim 1 furtherincluding material to secure the proximal region of the insert to thespine.
 6. An assembly according to claim 1 wherein the spine defines atleast two spine lumens, and wherein the insert is carried by at leastone of the spine lumens.
 7. An assembly according to claim 1 wherein thespine defines at least two spine lumens, and wherein the insert iscarried by one of the spine lumens to guide sliding movement of theelongated electrode element, and wherein the other spine lumen holdsanother functional element for use in concert with the elongatedelectrode element.
 8. An assembly according to claim 7 wherein thefunctional element comprises a temperature sensor.
 9. An assemblyaccording to claim 7 wherein the functional element comprises a fluidirrigation path.
 10. An assembly according to claim 1 wherein the spineis joined to several other spines to form a basket structure.
 11. Anassembly according to claim 1 wherein the spine defines at least twospine lumens, and wherein the insert is carried by at least one of thespine lumens to guide sliding movement of the elongated electrodeelement.
 12. An assembly according to claim 1 wherein the electrodesupport structure includes an array of spines joined together to form abasket structure.
 13. An electrode assembly comprising an elongatedelectrode element having a distal operative portion, a connector tocouple the elongated electrode element to a source of radio frequencyenergy, and an electrode support structure comprising at least one spinefor holding the elongated electrode element for use, the spineperipherally defining at least one spine lumen, the spine including aside opening, and an insert carried by the spine and peripherallydefining an insert lumen sized to accommodate forward and rearwardsliding movement of the elongated electrode element within the spine,the insert including a distal extension having a first outer dimensionsized for insertion into the spine lumen, the distal extension includingan open distal end, the insert also including a proximal region having asecond outer dimension greater than the first outer dimension and sizedto resist insertion into the spine lumen to thereby define a maximuminsertion length for the distal extension to place the open distal endin desired alignment with the side opening for guiding sliding movementof the distal operative portion of the elongated electrode elementtoward the side opening.
 14. An assembly according to claim 13 whereinthe spine includes an interior ramp depending from the side opening, andwherein the maximum insertion length locates the open distal end on theinterior ramp for guiding sliding movement of the distal operativeportion of the elongated electrode element toward the side opening. 15.An assembly according to claim 13 wherein the maximum insertion lengthkeeps the open distal end from projecting through the side opening. 16.An assembly according to claim 13 further including material to securethe proximal region of the insert to the spine.
 17. An assemblyaccording to claim 13 wherein the spine defines at least two spinelumens, and wherein the insert is carried by one of the spine lumens toguide sliding movement of the elongated electrode element, and whereinthe other spine lumen holds another functional element for use inconcert with the elongated electrode element.
 18. An assembly accordingto claim 17 wherein the functional element comprises a temperaturesensor.
 19. An assembly according to claim 17 wherein the functionalelement comprises a fluid irrigation path.
 20. An assembly according toclaim 13 wherein the elongated electrode element includes an axis, andwherein the distal operative portion assumes a bend along the axis whenoutside the side opening of the spine.
 21. An assembly according toclaim 13 wherein the electrode includes an axis, and wherein the distaloperative portion is biased to assume a bend along the axis when outsidethe side opening of the spine.
 22. An assembly according to claim 13wherein the elongated electrode element includes a proximal electrodeportion formed from a first material, and wherein the distal operativeportion is formed of a second material different than the firstmaterial.
 23. An assembly according to claim 13 wherein the elongatedelectrode element includes a proximal electrode portion that is sizeddifferently than the distal operative portion to resist entry of theproximal electrode portion into the insert lumen.
 24. An assemblyaccording to claim 15 proximal electrode portion is formed from a firstmaterial, and wherein the distal operative portion is formed of a secondmaterial different than the first material.
 25. An assembly according toclaim 13 further including a mechanism to control the extent of forwardand rearward sliding movement of the elongated electrode element withinthe spine.